Question

الجدول التالي يعبر عن الصيغ العامة لأربعة مركبات عضوية هي (D,C,B,A):

	(A)	(B)	(C)	(D)
	$C_nH_{2n+2}O_2$	$C_nH_{2n}O$	$C_nH_{2n+2}O_3$	$C_nH_nO$

أي الاختيارات التالية يعاد صحيحا؟

• A. الصيغة (A) لمركب يستخدم كوقود للسيارات.
• B. الصيغة (C) لمركب يستخدم في صناعة النسيج.
• C. الصيغة (B) لمركب يستخدم في مستحضرات التجميل.
• D. الصيغة (D) لمركب يستخدم في حفظ الأطعمة.

Answer 1

Answer: (B)

الصيغة (C) لمركب يستخدم في صناعة النسيج.

Answer 2

The question asks us to identify the correct statement regarding the general formulas of four organic compounds (A, B, C, D) and their uses. Let's analyze each compound's general formula and evaluate the corresponding statement.

1. Compound A: $C_nH_{2n+2}O_2$

   • This general formula corresponds to saturated acyclic compounds with two oxygen atoms. The degree of unsaturation (DoU) is $n + 1 - (2n+2)/2 = n + 1 - (n+1) = 0$.

   • Examples include diols (glycols) like ethylene glycol ($C_2H_6O_2$) and propylene glycol ($C_3H_8O_2$).

   • Statement (1): "الصيغة (A) لمركب يستخدم كوقود للسيارات." (Formula (A) is for a compound used as fuel for cars.)

     • Ethylene glycol is primarily used as an antifreeze and coolant in car radiators, not as a primary fuel. Ethanol ($C_nH_{2n+2}O$) is used as fuel, but it has only one oxygen atom. Therefore, this statement is incorrect.

2. Compound B: $C_nH_{2n}O$

   • This general formula corresponds to compounds with one degree of unsaturation (DoU = $n + 1 - 2n/2 = n + 1 - n = 1$). This means it can be an aldehyde, a ketone, a cyclic ether, or an unsaturated alcohol.

   • Examples include formaldehyde ($CH_2O$), acetaldehyde ($C_2H_4O$), and acetone ($C_3H_6O$).

   • Statement (3): "الصيغة (B) لمركب يستخدم في مستحضرات التجميل." (Formula (B) is for a compound used in cosmetics.)

     • Acetone ($C_3H_6O$) is commonly used in nail polish remover, which is a cosmetic product. Many aldehydes and ketones are also used as fragrance components in perfumes and other cosmetic formulations. This statement is plausible.

3. Compound C: $C_nH_{2n+2}O_3$

   • This general formula corresponds to saturated acyclic compounds with three oxygen atoms (DoU = $n + 1 - (2n+2)/2 = 0$).

   • A prominent example is glycerol ($C_3H_8O_3$), which is a triol (propane-1,2,3-triol).

   • Statement (2): "الصيغة (C) لمركب يستخدم في صناعة النسيج." (Formula (C) is for a compound used in textile industry.)

     • Glycerol is widely used in the textile industry as a humectant, plasticizer, lubricant, and softening agent for fibers. It is also used in dyeing and printing processes. This statement is highly accurate and a significant application of glycerol.

4. Compound D: $C_nH_nO$

   • This general formula indicates a high degree of unsaturation (DoU = $n + 1 - n/2 = n/2 + 1$). For example, if n=6, DoU = $6/2 + 1 = 4$, which is characteristic of an aromatic ring.

   • An example is phenol ($C_6H_6O$).

   • Statement (4): "الصيغة (D) لمركب يستخدم في حفظ الأطعمة." (Formula (D) is for a compound used in food preservation.)

     • Phenol is a strong disinfectant and antiseptic, but it is toxic and not used for food preservation. Common food preservatives like benzoic acid ($C_7H_6O_2$) or sorbic acid ($C_6H_8O_2$) do not fit the $C_nH_nO$ formula. Therefore, this statement is incorrect.

Conclusion: Comparing the plausible statements (2) and (3), the use of glycerol (fitting formula C) in the textile industry is a very direct, well-known, and significant application. While compounds of formula B are used in cosmetics (e.g., acetone in nail polish remover, fragrances), the statement about glycerol in textiles is a more universally recognized and defining application for a compound of its type. Thus, option (2) is the most accurate choice.